When I was updating this page, then coupon price was 529.99 USD for BAFANG BBS02B 48V 500W Mid-Motor Conversion Electric Bike Kit [EU] (in Banggood). It is from European warehouse! Just check coupons out (with price alert and history). Best price?
Latest coupon and price update (UTC):
Banggood (529.99 USD)
Banggood warehouse is located in Europe 
. Price? There’s only 1 record in my database, so I have no idea if the price is OK. We have found one coupon for this product!
Link: Banggood product page
Price without coupon: 539.99 USD
Coupon (529.99 USD): BGa8751e
(CouponsFromChina.com tip: coupon code has to be applied in shop’s cart after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): BGSPRING8OFF
(probably won’t work, but you can try them out)
Aliexpress
Here are coupons that you can use.
Price history and price alert
There is only one database record (it was for 529.99 USD), so you can’t see price history chart.
You can set price alert (for Banggood).